Fluid cooled dynamo electric machine

ABSTRACT

A dynamo electric machine in which there is at least one rotatable component mounted on a shaft wherein there is provided a de-aeration chamber connected to the shaft for rotation therewith, the shaft having an axial bore along which cooling fluid can flow and the de-aeration chamber being in communication with said axial bore so that cooling fluid flowing through the bore can pass into the chamber by centrifugal force where it is de-aerated.

United States Patent 1 Sharpe et al. Nov. 20, 1973 FLUID COOLED DYNAMOELECTRIC 3,461,331 8/1969 MACHINE 3,318,253 5/1967 3,626,717 12/1971[75] Inventors: Raymond Sharpe, Mirfield; Peter 3, 29 34 2 971 Hunt,Shipley, both of England 3,393,333 7/1968 [73] Assigneez Rotax L mitedBirmingham, 3,145,314 8/1964 Becker 310/61 England Primary Examiner-R.Skudy [22] 1971 Attorneyl-lolman & Stern [21] Appl. No.: 169,448

[57] ABSTRACT [30] Foreign Application Priority Data Aug 5 1970 GreatBritain 37 775/70 A dynamo electric machine in which there is at leastone rotatable component mounted on a shaft wherein here is rovided ade-aeration chamber connected to 52 US. 1. 10 1 t P E Int 8 1 43 theshaft for rotation therewith, the shaft having an [58] Field 53 54 58axial bore along which cooling fluid can flow and the 10/59 6de-aeration chamber being in communication with said axial bore so thatcooling fluid flowing through [56] References Cited the bore can passinto the chamber by centrifugal force where it is deaerated.

UNITED STATES PATENTS 11/1969 Potter 310/54 5 Claims, 1 Drawing FigureThis invention relates to dynamo electric machines and has as its objectthe provision of such a machine in a convenient form.

in accordance with the present invention there is provided a dynamoelectric machine having a rotatable shaft with at least one machinecomponent mounted on the shaft for rotation therewith said shaft havingan axial bore for the passage of cooling fluid, there being furtherprovided a de-aeration chamber which is connected to said shaft forrotation therewith, said chamber being in communication with said axialbore in said shaft so that cooling fluid will pass into said chamberwhere it is de-aerated or substantially de-aerated by centrifugal force.

Conveniently, said chamber has a plurality of baffles which are securedto the inner wall of said chamber and which extend radially inwardlytherefrom and each of said baffles is provided with at least oneradially extending aperture which communicates with an aperture formedin the wall of said chamber, the latter being further provided with anopening which communicates with an annular passage defined by astationary member such that the de-aerated or substantially de-aeratedcooling fluid will enter said passage from where it is removed by a pumpfor re-circulation whilst air, foam or excess cooling fluid or anycombination of the latter discharges through the aforesaid aperturesformed in said baffles.

The invention will now be more particularly described with reference tothe accompanying drawing which is a sectional view ofa dynamo-electricmachine according to the present invention in combination with atransmission system.

Referring now to the drawing, there is shown an alternator, by way ofexample, which includes a stator having stator windings 11. A shaft 13is journalled for rotation in a casing 12 of the alternator, bearingsbeing provided at each end of the shaft 13. The right-hand end of theshaft 13 (as viewed in the accompanying drawing) is adapted to receive adriving device for the alternator as will be described hereinafter.

A machine component in the form of a rotor assembly 14 is mounted on theshaft 13 for rotation therewith and windings 15 are mounted on a rotorcore 16 so as to provide a number of poles. The shaft 13 is formed withan axial bore 17 to provide a passage for the cooling fluid which ispumped (by means not shown) into said bore 17.

Cooling fluid distributor means which are indicated generally by thereference numeral 18 are also mounted on the shaft 13 for rotationtherewith for the purpose of discharging cooling fluid onto the rotorwindings. The cooling fluid distributor means 18 may be in anyconvenient form and may be as described in U.S. Pat. No. 3,689,786.

There is further provided a de-aeration chamber 19 which is connected tothe shaft 13 for rotation therewith. This chamber has a plurality ofbaffles 20 which are secured to the inner wall of the chamber 19 andwhich are spaced circumferentially around the interior of the chamber 19so that they extend radially inwardly therefrom. Each of the baffles 20is provided with at least one radially extending aperture 21 whichcommunicates with an aperture 22 formed in the wall of the chamber 19.The axial end of the chamber 19 remote from the shaft 13 is surroundedby an annulus 23 which projects outwardly from the end casing of atransmission system.

The transmission system itself has an output shaft 24 which serves as anoutput from a continuously variable ratio transmission unit 25. Theoutput shaft 24 drives a load shaft 26 which is coupled to the aforesaidshaft 13 of the dynamo-electric machine so that the rotor assembly l4and the shaft 13 are driven at a constant speed by the transmissionsystem. The input of the variable ratio transmission unit 25 istransmitted through a lay shaft 27 from a gear train which is indicatedby the reference numeral 28.

The transmission unit 25 is in the form of a frictional roller drivegear consisting of three toroidal discs 29,30 and 31 between which twosets of rollers 32 and 33 are in frictional rolling engagement, thecentral disc 30 being double sided. This central toroidal disc 30 isconnected to the lay shaft 27 (with freedom to move slightly axially)and is mounted on bearings around a sleeve member 34a. The outer disc 29is secured to the output shaft 24 for rotation therewith and so as to beaxially fixed with respect to the shaft 24, whilst the outer disc 31 isconnected to the output shaft for rotational movement therewith andaxial movement relative thereto. The drive ratio of the transmissionunit 25 is varied by altering in known manner the ratio angle of therollers, that is to say the angle about a tangential tilt axis whichdetermines the distance from the gear axis of which the rollers 32, 33engage the toroidal discs. The rollers 32,33 are shown at a ratio angleat which they engage the central disc 30 at an equal radius to that ofthe outer discs 29 and 31 respectively, thus the variable unit as showntransmits a drive at a 1:1 ratio.

The rollers 32, 33 are mounted in roller carriages 34b and control ofthe ratio angle is achieved by bodily moving carriages in substantiallytangential directions with respect to the gear axis,and by allowing therollers then to steer themselves towards a different ratio angle as ismore particularly described in British Pat. No. 1,146,321.

The aforesaid de-aeration chamber 19 is further provided at its endremote from the shaft 13 with an opening 35 which communicates with anannular passage 36 which is defined by the annulus 23. As shown in thedrawing a component such as a rectifier 37 may be mounted within thechamber 19 so that it can be cooled by any cooling fluid entering thischamber.

In use, the shaft 13 is driven by the transmission system at a constantspeed and cooling fluid is fed into the axial bore 17 formed in theshaft 13. Some of this cooling fluid will be discharged from the axialbore 17 via the fluid distributor means 18 onto the rotor windings 15.However, some of the fluid which enters the axial bore 17 will flow intothe chamber 19, it being understood that this cooling fluid will besubstantially aerated. The cooling fluid passing into the chamber 19will be flung outwardly against the outer walls of this chamber 19 bycentrifugal force, and the cooling fluid will form an annular layeragainst the inner surface of the wall of the chamber 19. Since thecooling fluid itself is heavier than air or foam, de-aerated orsubstantially deaerated cooling fluid will be disposed nearest the innersurface of the wall 19 whilst the foam and air will be disposed radiallyinwardly of this aforesaid de-aerated or substantially de-aeratedcooling fluid. The deaerated cooling fluid will then pass through theopening 35 into the annular passage 36 from where it may be removed by apump for re-circulation, such de-aerated cooling fluid may for examplebe used in the lubricating system of the transmission system. Air, foamor excess cooling fluid or any combination of the latter can, interalia, discharge through the apertures 21 which are formed in the baffles20. It will be appreciated that any cooling fluid which is disposedwithin the chamber 19 (when the shaft 13 is being rotated) and radiallyoutwardly of those ends of the apertures 21 remote from the wall of thechamber 19, then this cooling fluid will pass through the operning 35and into the annular pas- ,sage 36. Furthermore, any cooling fluid, airor foam which is in use disposed radially inwardly of the aforesaid endsof the apertures 21 will be discharged outwardly through these apertures21 formed in the baffles 20 and then through the apertures 22 formed inthe wall of the chamber 19, by centrifugal force.

Although in the above-described embodiment of the invention referencehas been made to the provision of a plurality of baffles 20 secured tothe inner surface of the chamber 19 these baffles may be replaced byradially extending tubes which project inwardly through the wall of thechamber 19 so that their innermost ends are disposed a predetermineddistance radially inwardly of the inner surface of the wall of thechamber 19. These tubes will thus serve the same purpose as theaforesaid apertures formed in the baffles 20.

We claim:

1. A dynamo electric machine having a rotatable shaft with at least onecomponent mounted on the shaft for rotation therewith, said shaft havingan axial bore for the passage of cooling fluid, there being furtherprovided a de-aeration chamber which is connected to said shaft forrotation therewith, said chamber being in communication with said axialbore in said shaft and having a plurality of baffles which are securedin said chamber and which extend radially inwardly therefrom, so thatcooling fluid will pass into said chamber where it is de-aerated bycentrifugal force.

2. A dynamo electric machine as claimed in claim 1 wherein each of saidbaffles is provided with at least one radially extending aperture whichcommunicates with an aperture formed in the wall of said chamber.

3. A dynamo electric machine as claimed in claim 1 wherein an opening isprovided in the wall of said chamber, said opening forming a directcommunication between said chamber and an annular passage which isdefined by a stationary member surrounding said opening.

4. A dynamo electric machine as claimed in claim 1 wherein there isprovided cooling fluid distributor means mounted on said shaft fordischarging cooling fluid onto said components.

5. A dynamo electric machine as claimed in claim 1 wherein a rectifieris mounted within said de-aeration chamber where it can be cooled by thecooling fluid entering said chamber.

1. A dynamo electric machine having a rotatable shaft with at least onecomponent mounted on the shaft for rotation therewith, said shaft havingan axial bore for the passage of cooling fluid, there being furtherprovided a de-aeration chamber which is connected to said shaft forrotation therewith, said chamber being in communication with said axialbore in said shaft and having a plurality of baffles which are securedin said chamber and which extend radially inwardly therefrom, so thatcooling fluid will pass into said chamber where it is de-aerated bycentrifugal force.
 2. A dynamo electric machine as claimed in claim 1wherein each of said baffles is provided with at least one radiallyextending aperture which communicates with an aperture formed in thewall of said chamber.
 3. A dynamo electric machine as claimed in claim 1wherein an opening is provided in the wall of said chamber, said openingforming a direct communication between said chamber and an annularpassage which is defined by a stationary member surrounding saidopening.
 4. A dynamo electric machine as claimed in claim 1 whereinthere is provided cooling fluid distributor means mounted on said shaftfor discharging cooling fluid onto said components.
 5. A dynamo electricmachine as claimed in claim 1 wherein a rectifier is mounted within saidde-aeration chamber where it can be cooled by the cooling fluid enteringsaid chamber.